void QgsMapLayerStyleManager::readXml( const QDomElement &mgrElement )
{
  mCurrentStyle = mgrElement.attribute( QStringLiteral( "current" ) );
  if ( mCurrentStyle.isEmpty() )
  {
    // For old project made with QGIS 2, we migrate to "default".
    mCurrentStyle = defaultStyleName();
  }

  mStyles.clear();
  QDomElement ch = mgrElement.firstChildElement( QStringLiteral( "map-layer-style" ) );
  while ( !ch.isNull() )
  {
    QString name = ch.attribute( QStringLiteral( "name" ) );
    if ( name.isEmpty() )
    {
      // For old project made with QGIS 2, we migrate to "default".
      name = defaultStyleName();
    }
    QgsMapLayerStyle style;
    style.readXml( ch );
    mStyles.insert( name, style );

    ch = ch.nextSiblingElement( QStringLiteral( "map-layer-style" ) );
  }
}
void QgsMapLayerStyleManager::readXml( const QDomElement& mgrElement )
{
  mCurrentStyle = mgrElement.attribute( "current" );

  mStyles.clear();
  QDomElement ch = mgrElement.firstChildElement( "map-layer-style" );
  while ( !ch.isNull() )
  {
    QString name = ch.attribute( "name" );
    QgsMapLayerStyle style;
    style.readXml( ch );
    mStyles.insert( name, style );

    ch = ch.nextSiblingElement( "map-layer-style" );
  }
}